Circular knitting machines



W 6, 1969 F. H. CARR-OTTE E 09 CIRCULAR KNITI ING MACHINES Filed July 26, 1967 {3 FREDERICK HENRY CARRUITE JOHN ERNEST ELLIS In venlors B DAVIS, HOXIE,

FAITHFULL 8c HAPGOOD, Their Attorne s United States Patent 3,442,098 CIRCULAR KNITTING MACHINES Frederick H. Carrotte and John Ernest Ellis, Leicester, England, assignors to A. Kirkland & Co. Limited, Syston, Leicester, England, a British company Filed July 26, 1967, Ser. No. 656,117 Claims priority, application Great Britain, July 29, 1966, 34,174/66 Int. Cl. D04b 9/38 U.S. CI. 66-50 4 Claims ABSTRACT OF THE DISCLOSURE cylinder.

This invention relates to circular knitting machines designed to knit patterned fabric, by which term we mean fabric having a pattern either in stitch configuration or in yarn colour or type.

The production of a patterned fabric is accomplished on a circular knitting machine by arranging for the cylinder needles to knit, tuck or miss according to a prearranged sequence. As each needle approaches each feeder the needle is selected either to be raised or not to be raised by the cams associated with that feeder. Different colours or types of yarn may be supplied to the various feeders for producing patterns of yarn colour or type.

One apparatus for selecting the needles to knit, tuck or miss in rotating cylinder machines uses pattern wheels. The term pattern wheel is taken to include all devices which are rotated at a prearranged speed in relation to the speed of the cylinder and have elements and element spaces thereon adapted to cooperate with the needles or with selector members on the cylinder for selecting needles in consecutive tricks in the cylinder to knit, tuck or miss according to the prearranged configuration of the elements and element spaces on the device.

It is possible to form each pattern wheel of two pattern wheel sections, each of which contacts alternate needles or selector members on the cylinder; this practice is known as half-gauging and enables the dimensions of each element to be increased. It is of course possible to form pattern wheels of more than two sections contacting other arrangements of needles or selector members. In such cases the term pattern wheel is to be taken to refer to the set of pattern wheel sections forming each unit.

One type of pattern wheel operates by having peripheral bits which bear against jacks in the tricks. The jacks, or parts of the jacks by, for example, making the jacks rockable as described in US. patent specification No. 3,240,032 and my pending US. application Ser. No. 652,825 are radially slidable in the tricks, between alternative inner and outer positions. Each jack is associated with a needle in the same trick and according to the radial position of the jack in the trick, depending upon the presence or absence of a bit in the pattern wheel, the same jack, a further jack, or the needle in the trick is positioned so as to be ready either to be raised or to be missed by a raising cam associated with the next feeder. Again, patterning is achieved by removing or retaining the bits on the pattern wheels. The invention is concerned with pattern wheels of this type, these being usually driven directly from the cylinder.

According to the present invention a circular knitting machine has geared to its cylinder at least one pattern wheel bearing peripheral elements adapted to move selector members on the cylinder radially with respect to the cylinder, the pattern wheel being so geared to the cylinder that it is rotatable at a peripheral speed between the highest and lowest linear speeds of each selector member in being moved, during rotation of the machine, from its outer to its inner position on the cylinder. Preferably the peripheral speed of the pattern wheel is equal to the average speed of the selector members in being so moved.

In machines embodying the present invention the sliding contact, which has existed in hitherto known machines between elements and selector members on the cylinder, has largely been eliminated. This sliding contact, which is particularly serious in fine gauge machines, tends to decrease the maximum safe running speed of the machines because of the risk of needle or selector member breakage.

Hitherto, to overcome the sliding contact, the elements on the pattern wheel have been made circumferentially wider than is otherwise necessary for engaging selector members so that they do not slide off the selector members before the desired radial movement thereof has been completed. This has reduced the number of elements which can be positioned on a pattern wheel of a given diameter.

The invention is illustrated, by way of example, by the accompanying drawing, in which:

FIGURE 1 is a sectional plan of a part of a cylinder and of a pattern wheel of a circular knitting machine, and

FIGURE 2 is a geometrical representation of the parts shown in FIGURE 1.

In FIGURE 1 a cylinder 1 has vertical tricks 2 in its outer surface. Slidably mounted in each trick is a jack 3 above which is a needle (not shown) and, if desired, other jacks (also not shown).

Around the cylinder there are one or more pattern wheels 4, of which only one is shown. On the periphery of each wheel is a number of bits 5. These bits can be removed to leave bit spaces 6, and on the wheel shown every third bit is removed.

The wheel 4 is fixed to a spindle (not shown) which is rotated by its being keyed to a pinion (also not shown) meshing with an annular gear (also not shown) on the cylinder. The pitch between adjacent tricks in the cylinder and the pitch between adjacent bits (and bit spaces) on the wheel is such that the bits cooperate with butts on the jacks in the tricks to determine the action to be taken by the needles associated with each of the jacks at the next feeder or feeders. With the wheel shown every third jack is left in its outer position whilst the other jacks are pushed into the cylinder. The sequence of the positions of the jacks determines the pattern in the fabric knitted.

In FIGURE 2 the pattern wheel 4 of FIGURE 1 is represented by a circle 11 which contacts an are 12 of a larger circle representing part of the cylinder 1 of FIG- URE 1. A further arc 13, concentric with the are 12, represents the line of the edges of the jack butts projecting from the cylinder.

The radius of the wheel is designated R whilst the radius of the are 12 is designated R and the radius of the are 13 is designated R The point at which the butts of the jacks following the are 13, when the cylinder rotates in the direction of the arrow A, meet the bits on the periphery of the wheel is 3 designated 14. The cylinder and wheel radii through the point 14 make angles c and B respectively with a line 15 joining the centres of the cylinder and the wheel.

The length of the arcuate path followed by a jack butt which is contacted by a wheel bit, and moved from its outer to its inner position in rotating from the point 14 to the line 15 is designated X whilst the corresponding length of the arcuate path followed by a butt which does not contact a bit, and therefore remains in its radially outer position, is designated Y. It will be appreciated that X is greater than Y, and that butts which follow the path X must be accelerated.

Taking now, as an example, an 18 guage circular knitting machine having 1680 needles, from the gauge and the number of needles, the radius R of the cylinder can be calculated to be 15.444 inches. If the jacks are designed so that their butts project from the cylinder by 0.14 inch, R =15.584 inches.

If it is decided now that the pattern wheel is to have 96 bits (and/or bit spaces), the theoretical value of the radius of the wheel can be calculated in the conventional manner by taking the jack butt pitch to be equal to the wheel bit pitch, as follows:

-=0.890 inch If the peripheral speed of the pattern wheel is to be increased in accordance with the invention, it is necessary also to increase the radius of the pattern wheel above the conventional radius, as determined above. The increased size of the pattern wheel is calculated below.

From the informtion available about the triangle formed between the centres of the cylinder and the wheel and the point 14, the values of the angles on and B can be found to be:

Hence, the length of the arc X=0.491 inch and the length of the arc Y:0.467 inch.

It will be seen that, hitherto, the number of bits and/ or bit spaces and the number of jack butts along the arcs X and Y has not been the same, because of the difference between the lengths of the arcs whilst the bit pitch on the pattern wheel has equalled the jack butt pitch on the cylinder. It is required now, for reasons apparent below, that the number of bits and/or bit spaces on the pattern wheel along the arc X shall be made equal to the number of jack butts along the arc Y. By increasing the pitch on the pattern wheel to compensate for the difference between the lengths of the arcs X and Y, the sliding contact between the pattern wheel bits and the jack butts over the arc X is very much decreased compared with conventional knitting machines. The sliding contact cannot be completely eliminated because the speed of the jack butts when moving along the arc X changes from a maximum value, near the point 14, to a minimum value as it approaches the arc 12. The speed of the pattern wheel is made, in this embodiment, an average of the speed of the jack butts over the arc X so that the sliding contact is decreased to the minimum attainable. The calculations for equalising the number of bits and/ or bit spaces along the arc X with the number of butts on the arc Y is as follows:

If we designate the new radius of the pattern wheel to be R the number of bits and/or bit spaces in the length and the number of butts in the length 1680 X Y Y 27TR3 If these are equated,

=0.935 inch which is larger than the pitch between adjacent jack butts on the cylinder:

=0.0578 inch It will be appreciated the number of bits and/ or bit spaces in the length of the arc X, which, in a pattern wheel having the new radius, equals the number of butts in the length of the arc Y, is not necessarily a whole number, indeed it would be coincidental if it were so.

The distance between the centres of the cylinder and the wheel is now 15.444 inch+0.935 inch=l6.379 inch.

From the desired gear ratio between the cylinder and the wheel and the distance between the centres of the cylinder and the wheel it is now possible to determine the pitch circle diameters for the gears for driving them.

If, for example, the gear ratio is to be the same as the ratio between the number of needles to the number of bits, i.e. 1680:96 (17 /2 to l), and the pitch circle diameter of the cylinder gear is designated D and that for the pattern wheel pinion D D +D =2 (l5.444+0.935)=32.758 inch and D1:D2 X

from which it can be found that D =30.987 inch and D =l.771 inch It can now be found that the cylinder gear can be constructed with 560 teeth of 18 diametral pitch in order for it to have a pitch circle diameter almost exactly equal to the calculated figure of 30.987 inch and similarly the wheel pinion can have 32 teeth of 18 diametral pitch.

It will be noticed that the pitch circle diameter of the cylinder gear is greater than the diameter of the cylinder itself, and the pitch circle diameter of the pattern wheel pinion smaller than the diameter of the pattern wheel. This makes the pattern wheel rotate during use of the machine, at a higher peripheral speed than the cylinder, the increased speed being compensated for by the increased pitch of the pattern wheel bits and/or bit spaces in relation to the pitch of the jack butts.

It can be calculated that the new peripheral speed of the pattern wheel is in fact greater than the speed of the jack butts when in either of their positions (i.e. when following either of the arcs 12 or 13) but that it is less than the maximum speed of the butts which occurs at the instant they start to leave the are 13 along the arc X for the are 12. Furthermore, within the limits of accuracy allowed by the machining tolerances of the parts involved, the peripheral speed of the pattern wheel equals the average speed of the jack butts in moving along the arc X. This is shown as follows:

If the cylinder is taken to revolve at 1 rpm, the pat- 17 /2 XZWX 0.935 102.8 inches/minute and the average speed of the jack butts over the length of the arc X is:

0.491X21rX 15.584

0.467 =102.8 inches/minute We claim:

1. A circular knitting machine comprising a needle cylinder, selector members on the cylinder to initiate knitting movement of the needles and a pattern wheel geared to the cylinder, said pattern wheel bearing peripheral elements adapted to move said selector members on the cylinder radially with respect to the cylinder, in which the pattern wheel is so geared to the cylinder that it is rotatable at a peripheral speed between the highest and lowest linear speeds of each selector member in being moved, during rotation of the machine, from its outer position to its inner position on the cylinder.

2. A circular knitting machine as claimed in claim 1, in which the peripheral speed of the pattern wheel is equal to the average speed of the selector members in being so moved.

3. A circular knitting machine as claimed in claim 1, in which each selector member is a jack at least part of which is radially slidable in a trick of the cylinder.

4. A circular knitting machine as claimed in claim 3, in which said jacks are rockably mounted in the cylinder.

WM. CARTER REYNOLDS, Primary Examiner. 

